JP2000074830A - High-speed measuring method and measuring system for temperature, concentration and chemical species by use of semiconductor laser spectroscopy - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the time series measurement of the temperature, concentration and chemical species of fuel gas present in a burning place with a high time resolution of a specified value or more by emitting a laser beam having a specified wavelength to a gas to be measured through an isolator and an optical fiber, and sweeping the wavelength of the laser beam. SOLUTION: Two laser beams λ1, λ2 of about 2 μm emitted from semiconductor lasers 1, 2 are transmitted in mixed state by a cell 13 filled with a gas to be measured as measuring light, and incident on photodiodes 26, 27. On the other hand, the laser beams λ1, λ2 are also incident on photodiodes 28, 29 as reference light. The photodiodes 26-29 output signals according to the incident light, the output signals are transmitted to an A/D converter 34 through preamplifiers 30-33, and the converted outputs are signal-processed by a computer. According to this, the temperature, concentration and chemical spices of the gas to be measured supplied to the cell 13 can be measured with a high time resolution of several tens KHz or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and system for high-speed measurement of temperature, concentration and chemical species using semiconductor laser spectroscopy.

[0002]

BACKGROUND OF THE INVENTION The use of semiconductor laser spectroscopy enables simultaneous measurement of the temperature and concentration of a plurality of chemical species with high time resolution in a time series, and the laser itself is small and has excellent robustness. Because of its easy handling and optical access through optical fibers, it is expected to be applied to measurement of various practical combustion devices and leak sensors.

[0003]

2. Description of the Related Art Conventionally, the main combustion products are mainly
Some H_TwoStudy on measurement of temperature, concentration, flow velocity, etc. of O
But recently, CH_Four, NO, C
O, CO _TwoIt is also applied to measurements such as. In particular,
In recent years, CO that has been attracting attention for global warming_TwoAbout
Is around 1.5 μm (one
Generally, it refers to the range of 1.3 to 1.5 μm).
There have been reports of concentration measurement using
You.

[0004]

However, since the above-mentioned wavelength band has a low absorption intensity, there is a problem that a long optical path length of several tens of meters is required, and the wavelength sweep speed of the external cavity semiconductor laser is limited. For,
There is a problem that measurement with high time resolution cannot be performed, the device is weak against vibration, and the device becomes large.

[0005] The present invention has been made in consideration of the above-mentioned matters, and an object of the present invention is to use a compact apparatus configuration so that fuel or combustion gas (for example, CH ₄ ,
_{CO, CO 2, H 2 O} , NO, chronological temperature, concentration, chemical species faster using a semiconductor laser spectroscopy can measure the temperature, concentration, chemical species with a high time resolution of several 10kHz of NO _2, etc.) It is to provide a measurement method and a measurement system.

[0006]

In order to achieve the above object, according to the present invention, a laser beam having a wavelength of about 2 μm is radiated to a gas to be measured via an isolator and an optical fiber, and the wavelength of the laser beam is swept. (Claim 1 and claim 7).

[0007] By using a semiconductor laser having a wavelength longer than the conventional one, ie, around 2 μm (generally, in the range of 1.8 to 2.2 μm), measurement can be performed with an absorption line having strong absorption. The required optical path length can be shortened, and the S / N in measurement of temperature, concentration, and chemical species can be improved. Then, as the waveform of the external input signal necessary for the wavelength sweep of the laser light, a straight line, a curve, a waveform including steps, more specifically, a sine wave, a ramp wave, a triangular wave,
Since any one of the pulse waves or a combination of any of them is appropriately used, high-speed sweeping can be performed, and temperature, concentration, and chemical species can be measured in a time series at high speed. In particular, when a sine wave is used as the waveform, it is possible to improve the frequency characteristics of the time response of a semiconductor laser, an amplifier, etc.
Wavelength sweeping at 10 M
Time series measurement of temperature, concentration and chemical species can be performed at high speed of Hz.

Then, two or more laser beams having different wavelengths may be sequentially oscillated (time-division oscillating). In such a case, optical means such as a duplexer becomes unnecessary, and the device configuration Can be simplified, and the robustness can be improved.

Further, two laser beams having different wavelengths may be oscillated as in bidirectional communication. In such a case, no optical means such as a duplexer is required, and the configuration of the apparatus is simplified. And robustness can be improved.

Further, an optimum wavelength may be used in each of a high-temperature region and a low-temperature region, or baseline interpolation may be performed in signal processing.

Further, by using two or more laser beams having different wavelengths, it is possible to compensate for disturbance such as dirt or vibration of a cell window or the like.

[0012]

Embodiments of the present invention will be described with reference to the drawings. First, the principle of simultaneous measurement of temperature, concentration, and chemical species by semiconductor laser spectroscopy will be described.
As shown in FIG. 9, when incident light having a wave number v from a semiconductor laser 81 is incident on a gas in a cell 82, the incident light is absorbed by the gas and received by a light receiving element 83. Obeys Lambert-Beer's law expressed by the following equation (1). (I / I _O ) _v = exp (−k _v L) (1) where I _O is the incident light intensity, I is the transmitted light intensity, L is the optical path length, and k _v is the absorption coefficient. . The absorption coefficient k _v is expressed by the following equation (2), and the integral absorption coefficient obtained by integrating the above with the frequency v is expressed by the following equation (3).

K _v = S (T) P _abs φ _v (2)

[0014]

Here, S (T) [cm ^-2 atm ^-1 ] is an absorption line transition intensity, P _abs [atm] is a partial pressure of a light absorbing gas, and φ _v [cm] is a linear function.

Each gas has a unique absorption wavelength band, and many absorption lines exist in the absorption wavelength band, for example, as shown in FIG. This FIG.
₂ shows the distribution of absorption lines in the ₂ (2 μm band). FIG. 3A shows the case where the temperature is 296 K, and FIG.
It is 50K.

Then, as shown in FIG.
One, for example, the wavelength λ₁Semiconductor laser
The absorption is measured by sweeping the oscillation wavelength. this
By taking the ratio between the waveform and the reference light waveform,
Measure the profile. In addition, the temperature measurement
Two absorption lines λ with different spectral profiles₁, Λ _Two
And their area ratio A₁/ A_Two(Or
Work height ratio P₁/ P _Two)
Can be.

When the above-mentioned spectral profile is obtained, the reference light waveform is not always necessary, and the baseline interpolation method can be used only from the measured light waveform obtained when the absorption is measured by sweeping the oscillation wavelength of the semiconductor laser. Is used, a spectrum profile can be obtained. That is, the measurement light waveform is the same as that of FIG.
In the case shown in the upper left of FIG. 1, a portion indicated by reference numeral X in the figure is obtained by a baseline interpolation method, and this is linearly connected to another non-absorbing portion (a virtual line indicated by reference numeral Y in the diagram). This is used as a reference light waveform.

In the case of a gas that forms one composite spectral profile from the spectral profiles of a plurality of absorption lines, the absorbance A of the composite spectral profile is expressed by the following equation (4). It is represented by the total area at the bottom. A = Σ (KL) = P _abs LS (T) (4)

Then, the absorbance is measured for the two composite spectrum profiles, and the temperature T is determined from the ratio R of the two profiles and the following equation (5).

[0021] Here, h [J · s] is Planck's constant, c [cm / s]
Is the speed of light, k [J / K] is the Boltzmann constant, and E "[c
m ^-1 ] is the energy of the level.

Then, the total pressure P [atm] and the optical path length L [c
m] is known, the temperature T obtained from the above equation (5)
The molar fraction of the measurement gas can be determined from the above equation (4). That is, the concentrations of the individual measurement target components are obtained.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual diagram for explaining a high-speed measuring method of temperature, concentration and chemical species using a semiconductor laser spectroscopy of the present invention and a measuring system (hereinafter simply referred to as a measuring system). 2 is a diagram schematically showing the configuration of the actual measurement system. Hereinafter, description will be made mainly with reference to FIG.

In FIGS. 1 and 2, reference numerals 1 and 2 denote semiconductor lasers as light-emitting portions, which emit laser beams having different wavelengths λ ₁ (for example, 1.996 μm) and λ ₂ (for example, 2.050 μm). It is composed of a feedback (DFB) semiconductor laser. These semiconductor lasers 1 and 2 are each current-controlled by a function generator 3. These semiconductor lasers 1 and 2 have a waveform including a straight line, a curve, and a step as an external input signal necessary for the wavelength sweep, and as a specific example, any one of a sine wave, a ramp wave, a triangular wave, and a pulse wave Are appropriately combined. Although not shown, these semiconductor lasers 1 and 2 each have an isolator for 2.0 μm.

Reference numerals 4 and 5 denote fiber couplers connected to the semiconductor lasers 1 and 2 via optical fibers 6 and 7, and reference numeral 8 denotes a laser beam emitted from each of the semiconductor lasers 1 and 2 to a cell 13 described later as measurement light. Fiber couplers 9 and 10 are optical fibers. The optical fibers 6 and 7 have optical fibers 1 for laser light as reference light.
1 and 12 are respectively connected.

Reference numeral 13 denotes a cell provided after the fiber coupler 8. Both ends of the cell 13 are sealed with cell windows 13a and 13b for transmitting a laser beam of about 2 μm, and a gas inlet 13c and a gas outlet 13d.
And gas supply lines 16 and 17 provided with on-off valves 14 and 15 so that, for example, CO ₂ and air can be supplied at an appropriate ratio.
A gas discharge line 20 provided with an on-off valve 18 and a vacuum pump 19 is connected to 3d. In this embodiment, mirrors 21 and 22 are provided outside the cell windows 13a and 13b, and the laser light incident on the cell 13 is emitted after passing through the cell 13 several times.

Reference numerals 23 and 24 denote collimators provided before and after the cell 13, respectively, and a duplexer 25 is provided after the collimator 24 on the rear stage. The splitter 25 separates laser light (measurement light) having two wavelengths transmitted through the cell 13 into laser lights having wavelengths λ ₁ and λ ₂ .

Reference numerals 26 and 27 denote photodiodes for measuring light, and reference numerals 28 and 29 denote photodiodes for reference light. These photodiodes 26 and 27 have wavelengths λ ₁ and λ ₂ separated by the demultiplexer 25. Laser light (measurement light) enters, and the optical fibers 1
Laser light (reference light) having wavelengths λ ₁ and λ ₂ is incident through 1 and 12.

Reference numerals 30 to 33 denote the photodiodes 26 to
The preamplifiers 30 to 33 are configured to be input to a signal processing device (for example, a computer) (not shown) via an A / D converter 34.

In the measuring system configured as described above, a gas in which CO ₂ and air are mixed at an appropriate ratio is supplied to the cell 13 as a gas to be measured. In this state, the laser beams λ ₁ and λ _{2 of} the two wavelengths respectively emitted from the semiconductor lasers 1 and ₂ pass through the cell 13 filled with the gas to be measured as measurement light in a mixed state. This measurement light becomes laser light of the original wavelengths λ ₁ and λ _{2 in} the demultiplexer 25 and enters the photodiodes 26 and 27. On the other hand, the laser beams λ ₁ and λ ₂ of two wavelengths respectively emitted from the semiconductor lasers 1 and ₂ are incident on the photodiodes 28 and 29 as reference light via the optical fibers 11 and 12 as they are.

The photodiodes 26 to 29
Then, signals corresponding to the incident light are output, and these output signals enter the A / D converter 34 via the preamplifiers 30 to 33, and the converted output is input to the computer and subjected to signal processing. The temperature, concentration, and chemical species of the gas to be measured supplied to the cell 13 are obtained.

[0032] In the measurement system in the above embodiment, the laser light used for the measurement, different wavelengths lambda ₁ of 2μm around a longer wavelength than conventional, because of the use of laser beam of lambda _2, strong absorption absorption Measurement can be performed with a line, and the required optical path length can be shortened, and the S / N in the measurement of temperature, concentration, and chemical species can be improved.

When the semiconductor lasers 1 and ₂ emit laser light having the wavelengths λ ₁ and λ ₂ , a waveform including straight lines, curves, and steps, as described above, in order to perform wavelength sweeping, specific examples Any one of a sine wave, a ramp wave, a triangular wave, and a pulse wave or a combination of any of them can be used as an external input signal. In particular, a sine wave signal is used as a sweep signal. As a result, the frequency characteristics of the time response of the semiconductor lasers 1 and 2 and the amplifier can be improved.
High-speed wavelength sweeping at 0 MHz becomes possible, thereby enabling time-series measurement of temperature, concentration, and chemical species at a high speed of 10 MHz.

In the above measurement, instead of measuring the entire spectrum profile of one absorption line,
As shown in FIG. 11, only the peak height of the spectrum is detected, and the temperature and concentration are calculated therefrom. At that time, the position of the peak of the spectrum shifts when the temperature, the concentration, the pressure, and the flow velocity fluctuate. Therefore, as shown in FIG. 12, the wavelength sweep is performed only in a narrow range near the peak, and the height of the peak is reliably detected. By doing so, the wavelength sweep range can be narrowed, and this can be used effectively even with a small number of samples, so that measurement can be performed at higher speed.

In the above-described embodiment, 2
Although the laser light of _two wavelengths λ ₁ and λ ₂ is separated using the demultiplexer 25, as shown in FIG. 3, the laser light of two wavelengths λ ₁ and λ ₂ is alternately time-division oscillated. You may.
That is, when the wavelength of the laser light from one semiconductor laser 1 is λ ₁ and the wavelength of the laser light from the other semiconductor laser 2 is λ ₂ as shown in FIG. Are λ ₁ and λ, as shown in FIG.
₂ , λ ₁ , λ ₂ ,... In this case, the duplexer 25 becomes unnecessary, the configuration of the measurement system is simplified, and the robustness of the measurement system is improved. The time-division optical system is not limited to those having wavelengths of only λ ₁ and λ ₂ , and may be plural as shown in FIG. In this case, the oscillation timing is λ ₁ , λ ₂ ,.
.., Λ _n , λ ₁ , λ ₂ ,.

In the above embodiment, the cell 13
Semiconductor lasers 1 and 2 are provided on one side and photodiodes 26 and 27 are provided on the other side.
As shown in FIG. 4, the semiconductor laser 1 is provided on one side of the cell 13 and the semiconductor laser 2 is provided on the other side, and a photodiode 26 corresponding to the semiconductor laser 1 is provided on the semiconductor laser 2 side and a semiconductor diode 2 corresponding to the semiconductor laser 2 is provided. Photo Died 2
7 may be provided on the semiconductor laser 1 side, respectively, and may be configured as if bidirectional communication. In this case, the duplexer 25 becomes unnecessary, the configuration of the measurement system is simplified, and the robustness of the measurement system is improved.

Incidentally, the absorbances of the absorption lines used for measurement have different temperature-dependent characteristics. Taking the ratio R of the absorbances of the two absorption lines, the combination is roughly classified into two types as shown in FIG. That is,
In this figure, the reference numeral A is for total temperature measurement, and the reference numeral B is for high temperature measurement. FIG. 6 shows the rate of change of the absorbance ratio R with respect to the temperature of the curves A and B. The larger this value is, the more accurate the temperature measurement becomes. In the curve indicated by the symbol A in FIG. 6, this value does not become zero, so that measurement over a wide temperature range is possible. Further, the curve indicated by the symbol B is zero near 700 K, which is not suitable for measurement near this temperature. However, when the temperature exceeds 900 K, the value becomes larger than that of the curve A. It can be said that the curve B is more suitable. Therefore, it is desirable to select an absorption line to be used depending on the temperature of the measurement object.

As exemplified in the above embodiment, the measurement system of the present invention is applicable not only to the case where the number of chemical species to be measured is single, but also to the case where there are a plurality of chemical species of two or more. Temperature and concentration can be measured individually. FIG.
Shows an example of a configuration for measuring the temperature and concentration of, for example, CO ₂ and H ₂ O. In FIG.
Reference numeral 2 denotes a CO ₂ measuring semiconductor laser which outputs laser beams having different wavelengths around 2 μm. 43, 44
Is a semiconductor laser for measuring H ₂ O, which outputs a laser beam having a wavelength different from that near 2 μm and different from the wavelength of the laser beam output from the semiconductor laser for measuring CO ₂ . The wavelength of the laser beam used here is preferably such that the absorption line near the wavelength is relatively isolated from the absorption lines of the same gas and another gas. For example, the absorption line for CO ₂ is
m, 2050.0 nm, 2053.8 nm, 2066.
5 nm, and the H ₂ O absorption line was 1899.6 nm;
1847.1 nm, 1817.0 nm, 1821.6n
m, 1808.6 nm. Therefore, when the chemical species to be measured is CO ₂ and H ₂ O, laser light is selected from the above-mentioned absorption lines so as to be a combination that increases the temperature measurement sensitivity depending on the temperature of the field to be measured. Is preferred.

In FIG. 7, reference numerals 45 to 48 denote fiber couplers, reference numerals 49 to 56 denote photodiodes provided downstream of the duplexer 25, photodiodes 49 to 52 for measuring light, and photodiodes 53 to 56 for reference. For light. It goes without saying that the optical path in this embodiment is configured using an optical fiber, as in the above-described embodiment.

Further, in the measurement system of the present invention, disturbances such as dirt and vibration of cell windows and the like can be compensated for by using laser beams having two or more different wavelengths. That is, as shown in FIG.
₁ and λ ₂ , when measuring at these wavelengths λ ₁ ,
using laser beams of different third wavelength lambda _a and lambda _2, which is irradiated to the cell 13 constitute a laser beam after the cell 13 transmitted to received by the photodiode 57, measuring the initial photodiode 57 Of the output voltage value _{Va0 of the} photodiode 57 and the output voltage value _Va1 of the photodiode 57 at the time of measurement, _Va0 /
V _a1 is obtained, and based on this, the degree of contamination of the cell window can be monitored.

Further, in the measuring system of the present invention, the Doppler shift effect can be used. In such a case, the moving speed of the gas in the cell 13 can be measured. Also, the pressure can be measured by the absorption effect of the absorption amount.

Next, application fields of the measurement system of the present invention will be described.

(Application to Automotive Engine) FIG. 13 schematically shows various application methods to engine measurement. In this figure, reference numeral 61 denotes an engine cylinder, 62 denotes an exhaust pipe, and 63 denotes an exhaust pipe. The designated catalyst device 64 is an EGR flow path. By providing a collimator 23 as a light-emitting side probe and a collimator 24 as a light-receiving side probe in each of these units 61 to 64, the measurement can be continuously performed in real time.

Measurement of temperature and concentration in engine cylinder Fig. 1
As shown in FIG. 4, by providing the sapphire engine cylinder 61 with the collimators 23 and 24 facing each other as probes, it becomes possible to measure the temperature, chemical species and concentration of gas in the engine cylinder 61.

NO in exhaust pipe_X・ CO_TwoTemperature
Time Series Measurement of Concentration As shown in FIG.
Meters 23 and 24 are provided, and mirrors 21 and 22 are provided.
, The H contained in the exhaust gas _TwoO, C
O_TwoMeasurement of temperature and concentration of various combustion products such as NO and NO
It is possible. High time resolution over kHz and time series measurement
Time variation of exhaust gas concentration
Measurement with a resolution equivalent to 1 degree crank angle
It is possible.

Monitoring of temperature rise of the catalyst in the catalyst device When the temperature of the catalyst is low immediately after starting the engine, the N
O Although _X suppressing effect is small, the as shown in Figure 13, when the collimator 23 to the catalytic converter 63 is provided to face each other, increase the NO catalyst temperature after engine start
It is possible to simultaneously measure the relationship with _X emissions,
The time course of the effect of the catalyst can be monitored in real time. Further, it is also possible to acquire data indicating at which position it is effective to provide the catalyst device 63. Furthermore, the correlation with formaldehyde generated at the time of cold start can be examined.

Measurement of Temperature of Distribution Gas to Each Cylinder in EGR As shown in FIG.
Are provided in parallel with each other, the collimators 23 and 24 are provided in the flow path 65 to each cylinder 61 to measure the concentration of the exhaust gas, thereby controlling the distribution ratio of the recirculated gas. Therefore, the combustion state in each cylinder 61 can be made uniform and optimized.

Monitoring of rise in the air temperature of the intake due to EGR gas In the EGR, the output decreases due to the rise in the gas temperature of the intake due to the EGR gas. Thereby, the relationship between the air temperature and the pressure of the intake can be checked, and the EGR and the engine performance can be uniformly evaluated.

Evaluation of performance of intake cooler By measuring the temperature of oxygen in the air of the intake, performance of the intake cooler can be evaluated.

Evaluation of turbo characteristics In addition, as described above, since the temperature of exhaust gas can be measured, it is possible to evaluate the performance of a turbo that relies on the conventional engine speed, boot pressure, and the like. Optimum design can be performed.

Temperature of each cylinder temperature / concentration set
Measurement of Concentration Fluctuation Then, it is also possible to measure the fluctuation of the gas temperature and concentration for each cylinder of the engine, and to measure the fluctuation thereof. Further, by measuring at each point of the exhaust pipe, the moving speed of the high-temperature gas can be measured. Thereby, it is possible to check whether or not there is a backflow of gas from the exhaust pipe to the cylinder, and it is possible to optimally design each cylinder and the collecting pipe.

Measurement of Temperature and Concentration near Spark Plug Further, a local temperature and concentration near the spark plug can be measured using a fiber sensor of a spark plug insertion type. As a result, the temperature of the mixed gas before ignition
The relationship between concentration and flame propagation can also be investigated.

Approach to the Mechanism of NO _X Generation By the way, NO _X is generated in the combustion of the engine, and this generation is greatly affected by the temperature of the combustion gas. And since the flow of the combustion gas in the engine is an oscillating flow, it may not be simple. So, CO
The temporal variation in the _second temperature is measured and at the same can be simultaneously by the amount of the NO _X also measured, examined the relationship between the generation of the bulk of the oscillating flow and NO _X in the combustion gases.

As described above, the measurement system of the present invention is very suitable for researching and designing an engine, but can also be applied to the following fields.

(Application to ultra-high-speed combustion field) Monitoring of mixed state of fuel and air In the combustor of a RAM or SCRAM jet engine,
Since the change in temperature greatly affects the chemical reaction characteristic time,
Mixing fuel and air is a major problem. Therefore, by measuring the change in concentration in a time series with high time resolution, it is possible to calculate the scale of the change, and it is possible to grasp the state of the mixing.

・ Mass Flux, Heat Flu
x, thrust measurement The temperature of the combustion gas is measured by the two-color method using two wavelengths.
Mass Flux, Heat Flux, and Thrust can be measured. As a result, conventionally, it was possible to measure only the time average, but it is possible to measure the time variation of the combustion efficiency in a transit state such as at the time of a stall or a sudden change in the number of revolutions.

(Application to Turbulent Combustion Field) Measurement of Variation Scale of Various Parameters Turbulent combustion is a very complicated phenomenon in which fluctuation due to turbulence and chemical reaction are combined. Therefore, the scale of fluctuation is obtained from the temporal fluctuation of the turbulence component of pressure, concentration, and velocity.
Each relationship can be estimated, and this data can be used for analyzing a complex reaction flow occurring in an actual machine.

(Application to Turbulent Field) Measurement of Mixing State by Gas Seeding In a turbulent field, mixing of fuel and air as an oxidant is a problem. Here, in a shear layer formed by two fluids of fuel and air, one fluid is seeded with CO ₂ or NO, and the concentration thereof is measured in a time series, whereby a mixed scale in the shear layer can be obtained. Since what is seeded is a gas rather than a particle, the problem of particle tracking can be avoided considerably. Such basic data in a high-speed flow or a high-pressure field is necessary for performing a simulation of an actual machine.

(Application to Gas Turbine) Control of Unstable Combustion If the fuel is lean, combustion becomes unstable and pressure fluctuations occur. Conventionally, has been measured using a pressure pick up the pressure fluctuations in the combustion chamber wall surface, unevenness of temperature and concentration of CH ₄ in the combustion chamber is believed to have an effect on the pressure fluctuation, the time variation monitoring Thereby, more stable combustion can be performed.

Monitoring of temperature and concentration under high pressure conditions It is possible to grasp the generation of CO ₂ when the load fluctuates and to monitor the temperature and concentration under high pressure conditions.
Conventionally, exhaust gas measurement is mainly performed at the outlet, but it is possible to measure fluctuations in temperature and concentration inside the combustor.

(Application to Furnace / Boiler) Real-time Control of Combustion Load Real-time monitoring of CH ₄ , NO and CO ₂ is possible, and real-time control of combustion load is possible. By monitoring the production status of NO, CO and CO ₂ , an unstable combustion factor is extracted and a feedback system for stability control is constructed.

(Application to Garbage Combustion Furnace) Dioxin Suppression and Combustion Control It is said that there is a correlation between the amount of CO and CO ₂ produced and the amount of dioxin produced, but their concentrations are monitored in real time. By controlling
It is possible to reduce dioxins caused by fluctuations in combustion load. In addition, by controlling the amount of CH ₄ , NO, and CO ₂ generated, real-time control of reburning reduction becomes possible.

(Application to domestic water heater)-Abnormal combustion sensor Monitoring of gas leakage and combustion instability is possible, and it can be used as a sensor when abnormal combustion occurs due to an increase in CO and NO emissions. .

(Application to Environmental Measurement)-Investigation of the Effect of Aircraft Exhaust Gas on the Atmosphere NO generated by high-temperature gas discharged from aircraft
_The influence on the atmosphere, such as _X and CO ₂ , can be examined. Conventional measuring instruments had poor time response, and it was extremely difficult to measure them on actual equipment due to problems such as the size of the equipment.However, the measuring system of the present invention is small and robust, Measurement is possible, and In-
The development of a flight measurement system is also possible.

(Application to Gas Leak Sensor) A leak sensor for CO ₂ from a can, as shown in FIG. 17, can be applied as a leak sensor from a beer can 66. With the conventional measurement method, it was difficult to detect a small amount of gas leaking from the beer can 66. However, the measurement system of the present invention is capable of high-speed real-time measurement. A defective product having a leak can be detected on the display 67.

[0066]

The method and system for high-speed measurement of temperature, concentration, and chemical species using semiconductor laser spectroscopy according to the present invention are capable of measuring the temperature, concentration, and chemical species of fuel and combustion gas present in a combustion field over several tens of kHz. Time series measurement can be performed with high time resolution. Further, the configuration of the entire apparatus is compact, and can be suitably implemented in various fields.

[Brief description of the drawings]

FIG. 1 is a graph showing the temperature and temperature using the semiconductor laser spectroscopy of the present invention.
FIG. 1 is a conceptual diagram of a high-speed concentration / chemical species measurement method and measurement system.

FIG. 2 is a diagram schematically showing an actual configuration of the measurement system.

FIGS. 3A and 3B are explanatory diagrams in the case of measurement using two wavelengths, FIG. 3A is a configuration diagram, FIG. 3B is a diagram showing a laser beam oscillation state, and FIG. , (D) are explanatory diagrams in the case of measurement using n wavelengths, (C) is a configuration diagram, and (D) is a diagram showing an oscillation state of laser light.

FIG. 4 is another configuration diagram when measurement is performed using two wavelengths.

FIG. 5 is a diagram for explaining the relationship between the absorbance ratio of two absorption lines and temperature.

FIG. 6 is a diagram for explaining the temperature dependence of the absorbance ratio.

FIG. 7 is a diagram schematically showing another configuration example of the measurement system.

FIG. 8 is a diagram illustrating monitoring of dirt on a cell window.

FIG. 9 is a diagram for explaining the measurement principle of the present invention.

FIG. 10 is a diagram showing a distribution of absorption lines of CO ₂ .

FIG. 11 is a diagram for explaining a wavelength sweep method.

FIG. 12 is a diagram for explaining a method of detecting an absorption peak by wavelength sweeping in a narrow range.

FIG. 13 is a diagram showing an example in which a probe of the measurement system is installed on an automobile engine.

FIG. 14 is a diagram showing an example in which the probe is installed in an engine cylinder.

FIG. 15 is a diagram showing an example in which the probe is installed in an exhaust pipe.

FIG. 16 is a diagram showing an example in which the probe is installed in an EGR.

FIG. 17 is a diagram showing an example in which the probe is used as a gas leak sensor in a beer can.

[Explanation of symbols]

 1, 2,... Semiconductor lasers.

 ──────────────────────────────────────────────────続 き Continued on the front page (71) Applicant 397047718 Yuji Ikeda 5-1-1207 Shinoharadai, Nada-ku, Kobe, Hyogo (71) Applicant 593036165 Seika Sangyo Co., Ltd. 3-3-1 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Ken Nakajima 3-19 Mefuyamate-cho, Takarazuka-shi, Hyogo (72) Inventor Yuji Ikeda 51-1207 Shinoharadai, Nada-ku, Kobe-shi, Hyogo (72) Inventor Miya ▲ saki ▼ Kazuhiro Hyogo 5F-2, Mukogaoka, Mita-shi E Building No. 402 F-term (Reference) 2G059 AA01 BB01 CC04 CC05 CC09 DD12 EE01 EE12 FF10 GG01 GG02 GG03 GG09 HH01 HH06 JJ13 JJ17 KK01 LL03 MM01 MM17 NN01

Claims (7)

[Claims] A laser beam of about 2 μm is irradiated on a gas to be measured via an isolator and an optical fiber,
A high-speed measurement method of temperature, concentration, and chemical species using semiconductor laser spectroscopy, wherein the wavelength sweep of the laser light is performed. 2. The high-speed measurement method of temperature, concentration, and chemical species using semiconductor laser spectroscopy according to claim 1, wherein laser beams having two or more different wavelengths are sequentially oscillated. 3. The high-speed measurement method of temperature, concentration, and chemical species using semiconductor laser spectroscopy according to claim 1, wherein laser beams having two different wavelengths are oscillated so as to face each other. 4. The high-speed measurement method for temperature, concentration, and chemical species using semiconductor laser spectroscopy according to claim 1, wherein the optimum wavelength is used in each of a high-temperature region and a low-temperature region. 5. The high-speed measurement method of temperature, concentration, and chemical species using semiconductor laser spectroscopy according to claim 1, wherein baseline interpolation is performed in the signal processing. 6. The high-speed measurement method of temperature, concentration, and chemical species using semiconductor laser spectroscopy according to claim 1, wherein disturbance is compensated by using two or more laser beams having different wavelengths. 7. A measurement target gas is irradiated with a laser beam of about 2 μm via an isolator and an optical fiber,
A high-speed temperature, concentration, and chemical species measurement system using semiconductor laser spectroscopy, wherein the wavelength sweep of the laser light is performed.